Electric drive unit for a motor vehicle, in particular for a motor car

Abstract

An electric drive unit includes a first electric engine having a first rotor, a second electric engine having a second rotor, and a transmission unit having a differential transmission with exactly three first shafts arranged coaxially with one another. The three first shafts are a sum shaft to which the first rotor is connected such that torques provided by the first rotor can be introduced into the transmission unit via the sum shaft, a first differential shaft coupled to a first vehicle wheel such that torques can be discharged from the transmission unit and transmitted to the first vehicle wheel via the first differential shaft, and a second differential shaft coupled to a second vehicle wheel such that torques can be discharged from the transmission unit and transmitted to the second vehicle wheel via the second differential shaft.

The invention claimed is: 
     
       1. An electric drive unit for a motor vehicle, the electric drive unit comprising:
 a first electric engine having a first rotor; 
 a second electric engine having a second rotor; 
 a transmission unit comprising
 a differential transmission having exactly three first shafts arranged coaxially with one another, wherein the exactly three first shafts are
 a sum shaft, to which the first rotor is connected such that torques provided by the first rotor are introducible into the transmission unit via the sum shaft; 
 a first differential shaft coupled to a first vehicle wheel such that torques are dischargeable from the transmission unit and transmitted to the first vehicle wheel via the first differential shaft; and 
 a second differential shaft coupled to a second vehicle wheel such that torques are dischargeable from the transmission unit and transmitted to the second vehicle wheel via the second differential shaft; and 
 a superimposed planetary gear set comprising three further shafts, wherein the three further shafts comprise
 a sun gear, to which the second rotor is coupled such that torques provided by the second rotor are introducible into the transmission unit via the sun gear; and 
 a planetary carrier; and 
 a ring gear connected or connectable to the first differential shaft or the second differential shaft in a manner fixed against rotation, 
 
 wherein the superimposed planetary carrier is connected to the sum shaft in a manner fixed against rotation, and 
 wherein the differential transmission is arranged coaxially with the first rotor, axially overlapping the first rotor and radially within the first rotor, 
 wherein the transmission unit further comprises
 a first transmission stage arranged between the first differential shaft and the first vehicle wheel in relation to a first torque flow extending from the first differential shaft to the first vehicle wheel, and 
 a second transmission stage arranged between the second differential shaft and the second vehicle wheel in relation to a second torque flow extending from the second differential shaft to the second vehicle wheel. 
 
 
 
 
     
     
       2. The electric drive unit of  claim 1 , further comprising: a first switch unit configured to
 connect the ring gear to the first differential shaft in a manner fixed against rotation, or 
 connect the ring gear to the second differential shaft in a manner fixed against rotation. 
 
     
     
       3. The electric drive unit of  claim 2 , further comprising:
 a second switch unit configured to connect the ring gear to a housing of the electric drive unit in a manner fixed against rotation. 
 
     
     
       4. The electric drive unit of  claim 3 , wherein the first switch unit is couplable to the second switch unit in such a way that the first and second switch units are switchable by a single actuator. 
     
     
       5. The electric drive unit of  claim 4 , wherein the first switch unit and the second switch unit are arranged axially overlapping the first rotor and radially within the first rotor, wherein the first switch unit is configured to connect the ring gear to the first differential shaft in a manner fixed against rotation. 
     
     
       6. The electric drive unit of  claim 4 , wherein the first switch unit is configured to connect the ring gear to the second differential shaft in a manner fixed against rotation, wherein, when viewed in an axial direction of the superimposed planetary gear set, the differential transmission, the superimposed planetary gear set, the second switch unit, and the first switch unit are arranged one after the other in the following order: 1) the differential transmission, 2) the superimposed planetary gear set, 3) the second switch unit, and 4) the first switch unit. 
     
     
       7. The electric drive unit of  claim 3 , wherein the first switch unit and the second switch unit are arranged axially overlapping the first rotor and radially within the first rotor, wherein the first switch unit is configured to connect the ring gear to the first differential shaft in a manner fixed against rotation. 
     
     
       8. The electric drive unit of  claim 1 , wherein the superimposed planetary gear set is arranged coaxially with the first rotor, axially overlapping the first rotor and radially within the first rotor. 
     
     
       9. The electric drive unit of  claim 1 , wherein the differential transmission is a bevel gear differential, wherein, when viewed in an axial direction of the first rotor, the first rotor, the differential transmission, the superimposed planetary gear set, and the second rotor are arranged one after the other in the following order: 1) the first rotor, 2) the differential transmission, 3) the superimposed planetary gear set, and 4) the second rotor.